The present invention provides novel hydroxyaromatic oligomers prepared from co-oligomerization reaction of a mixed cyanate of a polyphenol with a polymaleimide, as well as epoxy resin compositions prepared from said oligomers.
Preparation of hydroxyaromatic oligomers containing triazine groups and polyepoxides thereof is taught by R. E. Hefner, Jr., in U.S. Pat. No. 4,489,202 issued Dec. 18, 1984. The process disclosed therein uses an easily prepared mixed cyanate of a diphenol or polyphenol. More specificaly, the process disclosed comprises reacting at least one material having an average of more than one aromatic hydroxyl group per molecule with at least 0.01 but not more than 0.95 moles of cyanogen halide or mixture of cyanogen halides per aromatic hydroxyl group at a temperature and time sufficient to essentially complete the reaction and thereafter recovering the resultant cyanate mixture; trimerizing the resultant cyanate mixture in the presence of a suitable trimerization catalyst at a temperature and time to essentially complete the reaction, epoxidizing the resultant trimerized product in a conventional manner by reaction with an epihalohydrin with subsequent dehydrohalogenation with a basic-acting material and finally recovering the resultant triazine functional glycidyl ether product. Excellent control over the molecular weight and content of triazine groups is provided by this process. The resultant epoxy resin compositions possess unusually high thermal stability as well as excellent overall physical and mechanical properties.
Preparation of hydroxyaromatic oligomers containing triazine and oxazoline groups and polyepoxides thereof is taught by R. E. Hefner, Jr., in U.S. Pat. No. 4,487,915 issued Dec. 11, 1984. The process disclosed therein uses the aforementioned mixed cyanate of a diphenol or polyphenol. Co-oligomerization of this cyanate mixture with an epoxy resin, such as a diglycidyl ether of bisphenol A, provides hydroxyaromatic oligomers containing both triazine and oxazoline groups. Oligomers prepared from co-oligomerization of the mixed cyanate of a diphenol with an epoxy resin using mole ratios of epoxy groups to cyanate groups of about 1 to 10 to about 1 to 40 or more are disclosed for the process described. The oligomers, and unreacted diphenol, if any, are then epoxidized using methods well known in the art. The resultant epoxy resin compositions possess excellent thermal stability as well as enhanced mechanical properties.
Preparation of advanced epoxy resin compositions containing triazine groups or both triazine and oxazoline groups are taught by R. E. Hefner, Jr., in U.S. Pat. No. 4,506,063 issued Mar. 19, 1985. In the process disclosed therein, the respective triazine-containing or triazine-containing and oxazoline-containing hydroxyaromatic oligomers are reacted with an epoxy resin. The application discloses advanced epoxy resins as wel as cured compositions thereof.
Preparation of hydroxyaromatic oligomers containing triazine groups and iminocarbamate linkages is taught by R. E. Hefner, Jr. in U.S. Pat. No. 4,555,553 issued Nov. 26, 1985. The process disclosed therein uses the aforementioned mixed cyanate of a diphenol or polyphenol. Co-oligomerization of this cyanate mixture with an aromatic polyamine, such as methylenedianiline, provides hydroxyaromatic oligomers containing both triazine groups and iminocarbamate linkages. Oligomers prepared from co-oligomerization of the mixed cyanate of a diphenol with an aromatic diamine using mole ratios of amino groups to cyanate groups of about 1 to 5 to about 1 to 40 or more are disclosed for the process described. The oligomers, and unreacted diphenol, if any, are then epoxidized using methods well known in the art. The oligomers, and unreacted diphenol, if any, are reacted with an epoxy resin using methods well known in the art to provide advanced epoxy resin compositions. The resultant epoxy resin and advanced epoxy resin compositions possess unusually high mechanical strength.